Age-Related Expansion of Tim-3 Expressing T Cells in Vertically HIV-1 Infected Children

As perinatally HIV-1-infected children grow into adolescents and young adults, they are increasingly burdened with the long-term consequences of chronic HIV-1 infection, with long-term morbidity due to inadequate immunity. In progressive HIV-1 infection in horizontally infected adults, inflammation, T cell activation, and perturbed T cell differentiation lead to an “immune exhaustion”, with decline in T cell effector functions. T effector cells develop an increased expression of CD57 and loss of CD28, with an increase in co-inhibitory receptors such as PD-1 and Tim-3. Very little is known about HIV-1 induced T cell dysfunction in vertical infection. In two perinatally antiretroviral drug treated HIV-1-infected groups with median ages of 11.2 yr and 18.5 yr, matched for viral load, we found no difference in the proportion of senescent CD28⁻CD57⁺CD8⁺ T cells between the groups. However, the frequency of Tim-3⁺CD8⁺ and Tim-3⁺CD4⁺ exhausted T cells, but not PD-1⁺ T cells, was significantly increased in the adolescents with longer duration of infection compared to the children with shorter duration of HIV-1 infection. PD-1⁺CD8⁺ T cells were directly associated with T cell immune activation in children. The frequency of Tim-3⁺CD8⁺ T cells positively correlated with HIV-1 plasma viral load in the adolescents but not in the children. These data suggest that Tim-3 upregulation was driven by both HIV-1 viral replication and increased age, whereas PD-1 expression is associated with immune activation. These findings also suggest that the Tim-3 immune exhaustion phenotype rather than PD-1 or senescent cells plays an important role in age-related T cell dysfunction in perinatal HIV-1 infection. Targeting Tim-3 may serve as a novel therapeutic approach to improve immune control of virus replication and mitigate age related T cell exhaustion.     

Antibiotic resistance and plasmid profiling of Vibrio parahaemolyticus isolated from shrimp farms along the southwest coast of India

Shrimp, water, and sediment samples were collected from various shrimp farms located in and around Cochin. V. parahaemolyticus was identified by standard biochemical tests and plasmid profiling was carried out for the isolates. Susceptibility was tested against 15 antibiotics before and after the plasmid curing. Incidence of V. parahaemolyticus was found in 46% of the samples screened. Antibiogram studies showed, above 50% of the strains sensitive to chlorotetracycline, chloramphenicol and nitrofurantoin. Multiple antibiotic resistance (MAR) index was found to be 0.2. Total presumptive Vibrio parahaemolyticus count (TPVPC) and resistance to antibiotics was found to be more in sediment samples particularly in pre-monsoon season. Plasmid profiles of V. parahaemolyticus isolates revealed seven plasmids in the size range of 0.75, 1.2, 6.0, and 8.0 kb sizes and 3 plasmids above 10.0 kb. The MAR index suggests the low risk potential involved in consuming seafoods. Resistance to antibiotics did not vary even after curing of plasmids with sodium dodecyl sulphate suggesting that resistance to antibiotics in V. parahaemolyticus is chromosomal borne.     

Conjugation of Multiple Copies of Polyethylene Glycol to Hemoglobin Facilitated Through Thiolation: Influence on Hemoglobin Structure and Function

PEGylation induced changes in molecular volume and solution properties of HbA have been implicated as potential modulators of its vasoconstrictive activity. However, our recent studies with PEGylated Hbs carrying two PEG chains/Hb, have demonstrated that the modulation of the vasoconstrictive activity of Hb is not a direct correlate of the molecular volume and solution properties of the PEGylated Hb and implicated a role for the surface charge and/or the pattern of surface decoration of Hb with PEG. HbA has now been modified by thiolation mediated maleimide chemistry based PEGylation that does not alter its surface charge and conjugates multiple copies of PEG5K chains. This protocol has been optimized to generate a PEGylated Hb, (SP-PEG5K)₆-Hb, that carries ~six PEG5K chains/Hb – HexaPEGylated Hb. PEGylation increased the O₂ affinity of Hb and desensitized the molecule for the influence of ionic strength, pH, and allosteric effectors, presumably a consequence of the hydrated PEG-shell generated around the protein. The total PEG mass in (SP-PEG5K)₆-Hb, its molecular volume, O₂ affinity and solution properties are similar to that of another PEGylated Hb, (SP-PEG20K)₂-Hb, that carries two PEG20K chains/Hb. However, (SP-PEG5K)₆-Hb exhibited significantly reduced vasoconstriction mediated response than (SP-PEG20K)₂-Hb. These results demonstrate that the enhanced molecular size and solution properties achieved through the conjugation of multiple copies of small PEG chains to Hb is more effective in decreasing its vasoconstrictive activity than that achieved through the conjugation of a comparable PEG mass using a small number of large PEG chains.     

Effect of doxorubicin on heart mitochondrial enzymes in rats: a protective role for alpha-tocopherol.

Effect of doxorubicin on heart mitochondrial enzymes was studied in rats with or without the administration of alpha-tocopherol. Rats were treated with doxorubicin 2.5 mg/kg, ip body wt once a week for 8 weeks. Alpha-tocopherol was co-administered orally for 2 months (400 mg/kg body wt daily). TCA cycle enzyme, NADH-dehydrogenase, cytochrome-C-oxidase and Na+,K(+)-ATPase activities were found to be decreased in doxorubicin treatment. A significant decrease in protease activity was observed with a concomitant increase in mitochondrial protein level. Mitochondrial lipid peroxide level was found to be increased with a decrease in thiol content. Alpha-tocopherol co-administration was found to maintain the mitochondrial enzyme activities as well as the thiol content. The results are discussed with reference to the antioxidant nature of alpha-tocopherol.     

Sulfonamide phenylalanine (SPA) series of analogues as an antibacterial,antifungal, anticancer agents along with p53 tumor suppressor-DNA complex inhibitor – part 1

Abstract

A series of N-[1-benzyl-2-oxo-2-substituted(ethyl)] benzene/p-toluene sulfonamide (K1–K12) are synthesized. Structure of the synthesized analogues has been confirmed by FT-IR, ¹H & ¹³C NMR and ESI-MS spectroscopic techniques. All the synthesized analogues (K1–K12) have also been examined for their in-vitro antibacterial and antifungal activities. Compounds showed good antibacterial and antifungal activity against standard drug. Anticancer study has been carried out on three cancer cell lines PC-3, MCF-7 and A549 on two different concentrations (mg/mL and μg/mL). The K4 sulfonamide analogue showed better anticancer activity amongst all analogues against PC-3 and A549 cell lines. K4 inhibit G0/G1 phase in cell-cycle analysis experiment. All synthesized molecules (K1–K12) dock at junction p53-DNA and make hydrogen bonded with residues of p53 protein as per docking study. ADMET predictions of synthesized phenylalanine sulfonamide analogues (K1–K12) has been done using ‘Lipinski rule’ and it has been observed that all synthesized analogues did not violate the rule. Electronic, chemical properties and mulliken atomic charges of analogues were calculated using density functional theory (DFT).

Communicated by Ramaswamy H. Sarma     

Protective effect of Abutilon indicum against lead-induced reproductive toxicity in male Wistar rats

Despite ample literature on the toxic impact of lead on the environment and health, the exact mechanism of pathogenesis/toxicity is not clearly known. Because it is well established that lead induces oxidative stress, it is assumed that exposure to antioxidants may reduce the toxic impact of lead. In this study, we evaluated the impact of coadministration of the methanolic root extract of a plant Abutilon indicum (50, 100, 200 mg kg ⁻¹b.wt.) in mitigating the toxic impact of lead on the reproductive system of rats. In brief, Wistar rats were exposed to lead acetate in drinking water with or without coadministration of plant root extract and compared with that of control animals. After 45 days of exposure as outlined above, the animals were killed and the reproductive toxicity was assessed by sperm parameters, hormone and antioxidant enzyme assays, and testis histopathology. Significant reduction in testis weight, sperm count, testosterone levels, and antioxidant enzymes levels such as Superoxide Dismutase, Catalase, and Glutathione peroxidase was seen in lead-treated animals, confirming the toxic impact. The coadministration of A. Indicum (100 and 200 mg kg ⁻¹b.wt.) was found to bring the studied parameters close to the levels seen in untreated (control) animals. Our findings are indicative of the protective nature of A. Indicum against lead-induced reproductive toxicity in a dose-dependent manner. However, further characterization of the root extract is required to elucidate the probable mechanism of protection.     

N-glycolylneuraminic acid conjugates: implications of their absence in mammalian biochemistry

N-glycolylneuraminic acid (Neu5Gc) is one of the two most common forms of sialic acids present in glycoproteins and glycolipids of mammalian tissues. It is synthesized from the most ubiquitous sialic acid, N-acetylneuraminic acid (Neu5Ac) in a hydroxylation reaction catalysed by the enzyme Neu5Ac hydroxylase. Though Neu5Gc conjugates are prevalent in many tissues of mammals, they are absent in glycolipids and only trace amounts are present in glycoproteins of the brain and central nervous system. In humans Neu5Ac is the main sialic acid as Neu5Ac hydroxylase is inactive due to mutation of its gene. The importance of sialic acids in biochemical phenomena and the distinct roles played by specific forms of these amino sugars is adequately reflected in functional studies of selectin and sialoadhesin families of adhesion molecules. The absence of Neu5Gc, therefore, in tissues of humans and brain of mammals has raised interest, especially with regard to its impact on biochemical differences evident between humans and other mammals. It is suggested that though Neu5Gc conjugates are important in cellular interactions, their presence in brain and the central nervous system is deleterious to the latter's normal functions. Their interaction with other cellular components to form supramolecular associations is indicated that may have a bearing on major biochemical differences, a few of which are presently evident between humans and other mammals.     

In silico insights into the identification of potential novel angiogenic inhibitors against human VEGFR-2: a new SAR-based hierarchical clustering approach

Abstract

In this study, binding efficiency of new pyrrolopyrimidine structural analogs against human vascular endothelial growth factor receptor-2 (VEGFR-2) were elucidated using integrated in silico methods. Optimized high-resolution model of VEGFR-2 was generated and adopted for structure-based virtual screening approaches. Pyrrolopyrimidine inhibitor (CP15) associated compounds were screened from PubChem database and subjected to virtual screening and comparative docking methods against the receptor ligand-binding domain. Accordingly, high efficient compounds were clustered with similarity indices through PubChem structure cluster module using single-linkage algorithm. Moreover, pharmacokinetics including drug metabolism activities of high-binding leads under investigation was portrayed using ADMET and similarity ensemble analysis. Optimal energy orientations of the selected protein model have been shown to be reliable, and highly recommended for screening and docking studies. Docking and clustering strategies were shown that nineteen candidates as most effective binders for VEGFR-2 than CP15, and are grouped as three classes. Lys⁸⁶⁸, Glu⁸⁸⁵, Cys⁹¹⁹, His¹⁰²⁶, Arg¹⁰²⁷, Asp¹⁰⁴⁶, and Gly¹⁰⁴⁸ residues were predicted as novel hotspot residues, and participate in H-bonds, π-cation, π-stacking, halogen bonds, and salt-bridges formation with ligands. These additional bonds are contributing extent stability that holds the receptor structure at flexible state, this make difficult to any further conformational changes for evoking angiogenic signals. The ADMET and similarity ensemble analysis results were strongly indicated that thirteen candidates as best ligands for angiogenesis targets. Altogether, these findings indicate potential angiogenic templates and their binding levels with VEGFR-2; sorted viewpoints could be useful as a promising way to describe potential angiogenesis inhibitors with related molecular targets.